Method of forming a bite block

ABSTRACT

A bite block for use in a mouth of a patient to hold the mouth in a spaced-apart position that includes a condensed fiber block having a predetermined length suitable for being inserted into the mouth of the patient and positioned between upper and lower molars and a wrapper yarn repeatedly wrapped around the block along its length. An adhesive strand in the wrapper yarn is positioned on an outer surface of the fiber to maintain the block in its condensed state.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to a patient airway bite block of the generaltype used together with laryngeal mask airways (LMAs), oral endotrachealtubes (ETTs) and similar patient airways. A patient under generalanesthesia must have the airway maintained in an open position in orderto assure adequate ventilation. This is most often accomplished byintubating the patient using an LMA or an ETT. The LMA can serve inplace of either a patient facemask or an endotracheal tube andconstructed with a distal portion, which is a cuffed disc, which fitsaround the patient's larynx in the posterior hypopharynx and a moreproximal element, which is analogous to an endotracheal tube. LMAs areplaced in anesthetized patients blindly and the exiting tube portion ispositioned directly in the mid-line of the mouth.

Use of an LMA or an ETT in an anesthetized patient, requires a protocolthat assures that the patient's airway remains open and thus requiresthat certain events be avoided. First, the patient may bite down on theairway tube and cause airway obstruction. This can lead very quickly tohypoxemia (i.e., dangerously low levels of oxygen in the blood). Second,biting by the patient's incisors can cause actual severing of the LMA orETT and subsequent loss of control of the airway. Third, secretions tendto accumulate in the back of the throat during general anesthesiabecause there is a loss of the normal swallowing reflex in theanesthetized patient. In a lightly anesthetized patient or in a patientthat is awakening from general anesthesia, such secretions can causelaryngospasm and subsequent airway closure. Therefore, it is best tokeep the teeth apart with the soft bite block to allow these secretionsto be suctioned from the mouth. Because of the above-described problemsencountered using an LMA or an ETT, a bite block placed between theteeth of the anesthetized patient is necessary.

Conventional oral airways, which are usually used in patientsanesthetized with their airway secured with oral endotracheal tubes, arenot suitable for use with LMAs because such devices seat themselvesdirectly in the mid-line of the mouth and thus, compete for the spacewhere the tube portion of the LMA exits in the mouth. In addition, theposterior portion of the oral airway, which is used to hold the tongueforward when used with an endotracheal tube, impinges on the cuffedportion of the LMA in the hypopharynx resulting in the cuff notfunctioning properly. Among the solutions, practitioners have employedto provide bite blocks for patients with LMAs include the modificationof other products, which are intended for completely different uses. Forexample, a bite guard for use with gastroscopy patients has beendescribed for use as a bite block. This device is not suitable for usewith an LMA because (1) it is not designed for use with LMAs and is notsized appropriately, (2) it seats in the center of the mouth and (3) itis not safe for patients with frontal dental bridgework since this isthe area that will bite down on the device.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a biteblock that can be used with LMAs, ETTs and similar airway devices.

It is another object of the invention to provide a bite block that doesnot interfere with other oral appliances attendant to use of generalanesthesia during a medical procedure.

It is another object of the invention to provide a bite block that canbe held in the side of the mouth between the molars during use of an LMAor an ETT.

These and other objects and advantages of the invention are achieved byproviding a bite block for use in a mouth of a patient to hold the mouthin a spaced-apart position that includes a condensed fiber block havinga predetermined length suitable for being inserted into the mouth of thepatient and positioned between upper and lower molars and a wrapper yarnrepeatedly wrapped around the block along its length. An adhesive ispositioned on an outer surface of the fiber to maintain the block in itscondensed state. The bite block according to one preferred embodimenthas a density of 0.23 g/cm³ and a resistance to compression sufficientto maintain a thickness of at least 7 mm under an applied pressure of 7kg/cm².

According to another embodiment of the invention, the wrapper yarn hasat least two plies and one of the two plies is an adhesive adapted to bedissolved onto an outer surface of the sliver.

According to another embodiment of the invention, the adhesive strandcomprises cellulose acetate.

According to another embodiment of the invention, the fiber blockcomprises cotton sliver.

According to another embodiment of the invention, a bite block for usein a mouth of a patient to the mouth in a spaced-apart position isprovided, that includes a condensed, cylindrical cotton sliver blockhaving a predetermined length suitable for being inserted into the mouthof the patient between upper and lower molars. A yarn is repeatedlywrapped around the block along its length and an adhesive is positionedon an outer surface of the block and adapted to be dissolved onto anouter surface of the block to maintain the block in its condensed state.The wrapper yarn has two yarn plies and one of the two plies of the yarnis an adhesive.

According to another embodiment of the invention, the adhesive iscellulose acetate.

According to another embodiment of the invention, a method is providedfor forming a bite block for use in a mouth of a patient to hold themouth open in a spaced-apart position and includes the steps of forminga sliver and condensing the sliver into a sliver block. A yarn iswrapped repeatedly around the condensed sliver block along its lengthand an adhesive strand is applied onto an outer surface of the sliverblock to maintain the sliver in its condensed state. The sliver is cutinto a predetermined length suitable for being inserted into the mouthof the patient between upper and lower molars.

According to another embodiment of the invention, the step of condensingthe sliver into a sliver block includes the step of passing anuncondensed sliver through an orifice that narrows in a downstreamdirection sufficiently to condense the sliver into a desired dimensionperpendicular to the downstream direction of travel of the sliver.

According to another embodiment of the invention, the orifice iscircular in cross-section and condenses the sliver into a cylinderhaving a desired diameter.

According to another embodiment of the invention, the step of wrappingthe yarn includes the step of providing a yarn having at least twoplies, wherein at least one of the plies is an adhesive in the form of astrand.

According to another embodiment of the invention, the method includesthe step of dissolving the adhesive strand onto an outer surface of theblock along its length.

According to another embodiment of the invention, the step of formingthe sliver includes the step of forming the sliver from cotton staplefibers or any other natural of synthetic staple fibers.

According to another embodiment of the invention, at least one of theyarn plies is a non-dissolving synthetic strand.

According to another embodiment of the invention, the bite block isbetween 16-20 mm in diameter and between 8-12 cm in length.

According to another embodiment of the invention, the step of formingthe sliver block comprises the step of passing a plurality ofuncondensed slivers simultaneously through an orifice that narrows in adownstream direction sufficiently to condense the sliver into a desireddimension perpendicular to the downstream direction of travel of thesliver.

According to another embodiment of the invention, the method includesthe steps of condensing a sliver into a sliver block having a nominaldiameter of 8-12 mm, wherein under a compression load of 7 kg/cm² thediameter of the sliver block is at least 7 mm.

According to another embodiment of the invention, the method includesthe step of packaging a plurality of bite blocks for storage until use.

According to another embodiment of the invention, a method of forming abite block for use in a mouth of a patient to hold the mouth in aspaced-apart position is provided and includes comprising the steps offorming a plurality of cotton slivers and condensing the slivers into asliver block by passing a plurality of slivers simultaneously through anorifice that narrows in a downstream direction sufficiently to condensethe sliver into a desired dimension perpendicular to the downstreamdirection of travel of the sliver. A yarn having at least two plies iswrapped repeatedly around the condensed sliver block along its length,wherein at least one of the plies is an adhesive in the form of astrand. The adhesive strand is dissolved onto an outer surface of thesliver block along its length to maintain the sliver in its condensedstate and the sliver block is cut into a predetermined length to form abite block suitable for being inserted into the mouth of the patientbetween upper and lower molars. The bite block is packaged for storageuntil use. The sliver block has a nominal uncompressed diameter of 8-10mm, and under a compression load of 7 kg/cm² the diameter of the bitblock is at least 7 mm.

According to another embodiment of the invention, the adhesive strand iscellulose acetate, and the step of dissolving the adhesive includes thestep of passing the sliver block through an acetone bath.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The present invention is best understood when the following detaileddescription of the invention is read with reference to the accompanyingdrawings, in which:

FIG. 1 is an environmental view showing a bite block according to anembodiment of the invention positioned between upper and lower molars ofa patient before insertion of an airway;

FIG. 2 is a perspective view of a bite block according to an embodimentof the invention;

FIG. 3 is a side elevation of the bite block of FIGS. 1 and 2 with asection of wrapper yarn removed to show a covering layer of adhesiveoverlying the sliver block; and

FIG. 4 is a flow diagram illustrating a preferred process formanufacturing the bite block according to the disclosure of thisapplication.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, a bite block according to a preferredembodiment of the invention is shown at reference numeral 10. The biteblock 10 is formed of a tightly condensed bundle of fibers forming afiber block 12 that is wrapped in the tightly condensed state with awrapper yarn 14 applied, for example, by a braiding machine. A preferredsliver block 12 comprises staple cotton processed under medical gradecleanliness standards applicable to other medical products containingcotton. Other staple fibers can also be used, but staple cotton fiberhas been found to be a preferred, suitable material. The wrapper yarn 14preferably comprises a two-ply yarn wherein one ply is a syntheticfilament yarn such as nylon, polyester, polyethylene, polypropylene orother suitable material, with nylon being the preferred filament yarn.The second ply is preferably a cellulose acetate yarn.

As is shown in FIGS. 1 and 2, the wrapper yarn 14 is wrapped on thebraiding machine in a crisscross pattern around the cylindrical sliverblock 12 and prevents the condensed sliver block 12 from blooming, asdescribed in further detail below.

Referring to FIG. 3, the cellulose acetate yarn ply is dissolved duringthe manufacturing process described below and diffuses onto the surfaceof the sliver block 12. The diffused cellulose acetate acts as anadhesive 16 that further prevents blooming of the sliver block 12 andthus maintains the required compression of the bite block 10. Apreferred nominal diameter for the bite block 10 as manufactured isabout 20 mm.

FIG. 4 illustrates a preferred manufacturing process for the bite block10. Fiber, such as cotton staple fiber, is opened and then carded byconventional textile processing equipment. The output of the cards is asliver—a rope of parallel fibers with sufficient twist applied to holdthe sliver block 12 together during subsequent processing. As shown,several slivers, for example, three slivers are formed into a single,tightly condensed sliver block 12 by simultaneously passing the sliversthrough a “trumpet”, i.e., a funnel-shaped device with adownstream-narrowing orifice. Thus, for example, three 333-gram sliversare condensed into a single 1000-gram sliver block 12. Immediately atthe downstream opening of the trumpet, the joined, condensed slivers arewrapped with the wrapper yarn 14 in a braiding machine, which may be anyone of several types of braiding machines, such as a maypole braider.

In the preferred embodiment disclosed, the wrapped sliver block 12 isthen conveyed to and through a bath of acetone in which the celluloseacetate yarn ply is dissolved into a thin film that coats the surface ofthe sliver block 12 and provides further resistance to the naturaltendency of a compressed cotton fiber to bloom. The acetone has a verylow vapor pressure and rapidly evaporates, leaving the sliver block 12with both a wrapper yarn 14 of the remaining nylon component and anextremely thin adhesive coating 16.

Upon exiting the acetone bath, the continuous length of sliver block 12is cut to an intermediate length, for example, 10 cm. These individualcut lengths of sliver blocks 12 may be packaged individually or bundledinto groups of, for example, ten and packaged in a tube sufficientlylarge enough to accommodate the group and wrapped in a tubular paperpackage. The intermediate length sliver blocks 12 are then cut to afinal length, for example, 100 mm and are then ready for consolidationinto cartons for shipping.

The resulting bite block 10, according to one preferred embodiment, hasa density of 0.23 g/cm³ and a resistance to compression sufficient tomaintain a thickness of at least 7 mm under an applied pressure of 7kg/cm². The 7 mm minimum thickness under this degree of applied pressureis required because 7 mm is a standard diameter of an adult airway tube,and the force applied by a patient biting the bite block 10 should notrestrict the airway.

A bite block according to the invention has been described withreference to specific embodiments and examples. Various details of theinvention maybe changed without departing from the scope of theinvention. Furthermore, the foregoing description of the preferredembodiments of the invention and best mode for practicing the inventionare provided for the purpose of illustration only and not for thepurpose of limitation, the invention being defined by the claims.

We claim:
 1. A method of forming a bite block for use in a mouth of apatient to hold the mouth open in a spaced-apart position, comprisingthe steps of: (a) forming a sliver; (b) condensing the sliver into asliver block; (c) wrapping a yarn repeatedly around the condensed sliverblock along its length, wherein the step of wrapping the yarn includesthe step of providing a yarn having at least two plies, and furtherwherein at least one of the plies is an adhesive in the form of astrand; and (d) severing the sliver into a predetermined length suitablefor being inserted into the mouth of the patient between upper and lowermolars.
 2. A method according to claim 1, wherein the step of condensingthe sliver into a sliver block includes the step of passing anuncondensed sliver through an orifice that narrows in a downstreamdirection sufficiently to condense the sliver into a desired dimensionperpendicular to the downstream direction of travel of the sliver.
 3. Amethod according to claim 2, wherein the orifice is circular incross-section and condenses the sliver into a cylinder having a desireddiameter.
 4. A method according to claim 1, and including the step ofdissolving the adhesive strand onto an outer surface of the block alongits length.
 5. A method according to claim 1, wherein the step offorming the sliver comprises the step of forming the sliver from cottonstaple fibers.
 6. A method according to claim 1, wherein at least one ofthe yarn plies comprises a non-dissolving synthetic strand.
 7. A methodaccording to claim 1, wherein the bite block is between 8-10 mm indiameter and between 8-12 cm in length.
 8. A method according to claim1, wherein the step of forming the sliver block comprises the step ofpassing a plurality of uncondensed slivers simultaneously through anorifice that narrows in a downstream direction sufficiently to condensethe sliver into a desired dimension perpendicular to the downstreamdirection of travel of the sliver.
 9. A method according to claim 1,wherein the sliver block has a nominal diameter of 16-20 mm, whereinunder a compression load of 7 kg/cm2 the diameter of the sliver block isat least 7 mm.
 10. A method according to claim 1, and including the stepof sealing the bite block into an aseptic package for storage until use.11. A method of forming a bite block for use in a mouth of a patient tohold the mouth in a spaced-apart position, comprising the steps of: (a)forming a plurality of cotton slivers; (b) condensing the slivers into asliver block by passing the plurality of slivers simultaneously throughan orifice that narrows in a downstream direction sufficiently tocondense the slivers into a desired dimension perpendicular to thedownstream direction of travel of the slivers; (c) wrapping a yarnhaving at least two plies repeatedly around the condensed sliver blockalong its length, wherein at least one of the plies is an adhesive inthe form of a strand; (d) dissolving the adhesive strand onto an outersurface of the sliver block along its length to maintain the sliverblock in its condensed state; (e) severing the sliver block into apredetermined length to form a bite block suitable for being insertedinto the mouth of the patient between upper and lower molars; (f)sealing a plurality of bite blocks into paper sleeve, wherein the sliverblock has a nominal uncompressed diameter of 16-20 mm, wherein under acompression load of 7 kg/cm2 the diameter is at least 7 mm.
 12. A methodaccording to claim 11, wherein the adhesive strand comprises celluloseacetate and the step of dissolving the adhesive comprises the step ofpassing the sliver block through an acetone bath.